jackj
New Member
Posts: 21
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Post by jackj on May 17, 2023 22:44:04 GMT
Hi everyone! Let me just start by saying that this is my first post here on these forums. I've been doing some research online about the issue I'm facing, but could not find anything useful. I have a 60s frigidaire cycla-matic refrigerator/freezer that I just recently found out is no longer cooling. Let me also state that I am by no means an expert on these vintage machines, but I do have an elementary understanding of the operating principles involved. I found this forum and thought I'd be able to get some expert advice. The main things I noticed since I lost cooling are: 1. The compressor is not seized and seems to be running normally. 2. After shutting the machine off and letting the compressor cool to room temperature then turning the machine back on, things will return to normal for a few minutes with the unit cooling in the freezer section (the refrigerator evaporator coil is only slightly cool) and the condenser coils getting very warm to the touch, I can also hear gas flowing through the system as well. Then after about 10 minutes I lose cooling and the condenser coil is only slightly warm to touch and both evaporator coils return to room temperature. I would put gauges on the system, but I don't have a hermetic service kit. I slightly loosened the nut on the service port to check for gas and there was plenty of pressure there. Any thoughts on what my problem may be? I'm inclined to believe a leak may have developed, but I got a lot of pressure flowing out when I cracked the service port nut. Maybe the compressor has failing valves that aren't sealing properly anymore as things warm up? I have attached some pictures to this post for reference. Any input or advice would be greatly appreciated and it is nice to meet you all!
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Post by ckfan on May 18, 2023 16:04:55 GMT
That sounds like a classic case of moisture in the system blocking the capillary tube. More than likely the compressor is fine, but running it like this long term may damage it since the blockage (ice crystals) will cause excess pressure on the outlet side. What will need to be done is to evacuate the system. I’m not sure if it would be wise to recover the charge or not. Then you would have to install a filter drier where the capillary tube enters the condenser coil. Then the system would need to be pulled into a vacuum and put refrigerant back in. I have a fridge that exhibits this exact symptom.
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marko
7 Cubic Foot
Posts: 144
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Post by marko on May 18, 2023 22:39:41 GMT
That sounds like a classic case of moisture in the system blocking the capillary tube. More than likely the compressor is fine, but running it like this long term may damage it since the blockage (ice crystals) will cause excess pressure on the outlet side. What will need to be done is to evacuate the system. I’m not sure if it would be wise to recover the charge or not. Then you would have to install a filter drier where the capillary tube enters the condenser coil. Then the system would need to be pulled into a vacuum and put refrigerant back in. I have a fridge that exhibits this exact symptom. What ckfan said is very likely. The fact that the condenser gets very warm may indicate that the refrigerant charge is low. Moisture freezing would tend to cause the condenser to go cool after some run time. Also, since neither evaporator cools for long,I would suspect both moisture freezing in the system and a low charge, which can go hand in hand, especially with a low side leak.
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jackj
New Member
Posts: 21
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Post by jackj on May 18, 2023 23:25:33 GMT
That sounds like a classic case of moisture in the system blocking the capillary tube. More than likely the compressor is fine, but running it like this long term may damage it since the blockage (ice crystals) will cause excess pressure on the outlet side. What will need to be done is to evacuate the system. I’m not sure if it would be wise to recover the charge or not. Then you would have to install a filter drier where the capillary tube enters the condenser coil. Then the system would need to be pulled into a vacuum and put refrigerant back in. I have a fridge that exhibits this exact symptom. Thanks for the insight marko and ckfan, glad that the issue I'm facing is not completely unknown. My next questions are: 1. Would I add the drier to the capillary tube coming out of the flying saucer shaped device (drier?) coming off of the bottom of the condenser coil then wrapping around the suction line on the far left of the unit? 2. Can I use 152a as a substitute to the r12 this systems uses? and 3. Since I don't have a hermetic service kit, would I be able to use a supco bullet piercing valve as a way to charge/check pressures and which line would I install one on? This compressor has 4 lines going into it in total. I have attached a few more photos of the refrigerant lines and the wiring diagram in hope it paints a clearer picture. Thanks!
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Post by ckfan on May 19, 2023 15:45:31 GMT
I believe some of those later meter misers had an oil cooling loop which may be what the other two lines are for, not entirely sure.
Usually, the drier will be attached right where the capillary tube begins, after the condenser.
Yes, 152a can replace R12. It won’t be pound for pound though. You have to slowly add it and experiment until you get a good frost line and don’t have a sweating return line going to the compressor, indicating an over charge.
Those bullet piercing valves are not ideal. While they are great for gaining access to a system with no ports, that’s really all they should be used for. They will leak over time. It’s almost guaranteed. They aren’t super well made and all that is separating the hole it punches in the line from the outside air is a little bit of rubber seal clamped around the line. I only try to use them to get refrigerant out of a system that has no other means to gain access to the system. Hermetic service kits are available on EBay and I would suggest that you try to get one of those first.
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Post by turbokinetic on May 20, 2023 12:24:22 GMT
This does sound like a moisture blockage problem. Sometimes the compressor its self can release moisture from the materials used in its construction. There is a drier on this system, where the small wire-like capillary tube joins the condenser outlet. You'll need to remove the original one and replace it with a new one, in order to prevent possible recurrence of the problem. These are high-side housing compressors, if I am not mistaken. (I can't be 100% sure because the design is slightly different from the ones I've worked on) That means it's extremely easy to overcharge it because additional charge takes a very long time to stabilize. After you replace the drier and run the vacuum pump overnight, you should charge in about 1/3 of a can of refrigerant (2 ounces R12 or 3 ounces R152A would be reasonable) and allow the system to run for at least 30 minutes before making any determination of the charge level. The reason for the 4 lines is because this compressor has a precooler coil, also known as a de-superheat coil. This takes hot discharge gas from the compressor pump mechanism and cools it off. This then recirculates through the compressor motor housing to cool the motor. The last smaller line is the outlet to the condenser. The lines to the precooler and condenser are part of the high-side of the system. The larger line at the bottom, with the suction screen identified in the attached picture is the low side return line. The factory charged these through the high side with special equipment for pressure charging. I would recommend charging through the low side using conventional methods. For someone just learning, that is much easier. Sincerely, David
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jackj
New Member
Posts: 21
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Post by jackj on May 21, 2023 14:43:16 GMT
Thanks for the very helpful tips and information ckfan and David! I went ahead and ordered a hermetic service kit off ebay which should arrive early next week so hopefully I'll be able to get a better idea of what the system is doing by putting some gauges on. In regard to this compressor being a high side dome, if I were to charge the system from the high side, would I charge only liquid in roughly 3oz increments while the system is off then run for 30 minutes then power off and allow the system to equalize then rinse and repeat until i get a good frost on both evaporators? The original r12 charge on this system was 24oz by the way.
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Post by turbokinetic on May 22, 2023 13:35:31 GMT
Thanks for the very helpful tips and information ckfan and David! I went ahead and ordered a hermetic service kit off ebay which should arrive early next week so hopefully I'll be able to get a better idea of what the system is doing by putting some gauges on. In regard to this compressor being a high side dome, if I were to charge the system from the high side, would I charge only liquid in roughly 3oz increments while the system is off then run for 30 minutes then power off and allow the system to equalize then rinse and repeat until i get a good frost on both evaporators? The original r12 charge on this system was 24oz by the way. That sounds like a good plan! But be warned, the 24 ounce charge was a maximum theoretical charge for that compressor in any system and likely the system only needed about half that. You'll need to pressure-charge the system by heating the can (carefully) to drive the vapor from the can into the machine, to charge in the manner you're considering.
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jackj
New Member
Posts: 21
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Post by jackj on May 22, 2023 18:35:43 GMT
Thanks for the very helpful tips and information ckfan and David! I went ahead and ordered a hermetic service kit off ebay which should arrive early next week so hopefully I'll be able to get a better idea of what the system is doing by putting some gauges on. In regard to this compressor being a high side dome, if I were to charge the system from the high side, would I charge only liquid in roughly 3oz increments while the system is off then run for 30 minutes then power off and allow the system to equalize then rinse and repeat until i get a good frost on both evaporators? The original r12 charge on this system was 24oz by the way. That sounds like a good plan! But be warned, the 24 ounce charge was a maximum theoretical charge for that compressor in any system and likely the system only needed about half that. You'll need to pressure-charge the system by heating the can (carefully) to drive the vapor from the can into the machine, to charge in the manner you're considering. Thanks David. Only reason I'm going to try to charge through the high side first is because I'd rather not mess with any other lines other than the condenser outlet line that I will have to braze a new drier to. If charging through the high side doesn't go as planned, then I'll add a port on the suction line. One more thing I want to clear up is should I be charging liquid only to the high side thus making sure the can is either tilted or inverted to ensure that only liquid refrigerant is entering the compressor or should I be charging gas only like I would if I went through the suction line? Also, I decided to turn on the system again after letting it sit for a few days just to see if anything had changed and it seems like I definitely have a low charge situation along with the probable moisture blockage. Only a few runs of the evaporator in the freezer compart frosted up while the rest of the evaporator was cool but not ice cold. I also noticed that the refrigerator compartment evaporator remained at room temperature with only a slight bit of coldness at the beginning of the evaporator line. I turned the system off after about 10 minutes which was before the moisture blockage problem could occur so I don't think I hurt anything but I'm not going to run the system anymore until the hermetic service kit arrives this wednesday and I can get some gauges on.
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Post by turbokinetic on May 22, 2023 19:58:50 GMT
That sounds like a good plan! But be warned, the 24 ounce charge was a maximum theoretical charge for that compressor in any system and likely the system only needed about half that. You'll need to pressure-charge the system by heating the can (carefully) to drive the vapor from the can into the machine, to charge in the manner you're considering. Thanks David. Only reason I'm going to try to charge through the high side first is because I'd rather not mess with any other lines other than the condenser outlet line that I will have to braze a new drier to. If charging through the high side doesn't go as planned, then I'll add a port on the suction line. One more thing I want to clear up is should I be charging liquid only to the high side thus making sure the can is either tilted or inverted to ensure that only liquid refrigerant is entering the compressor or should I be charging gas only like I would if I went through the suction line? Also, I decided to turn on the system again after letting it sit for a few days just to see if anything had changed and it seems like I definitely have a low charge situation along with the probable moisture blockage. Only a few runs of the evaporator in the freezer compart frosted up while the rest of the evaporator was cool but not ice cold. I also noticed that the refrigerator compartment evaporator remained at room temperature with only a slight bit of coldness at the beginning of the evaporator line. I turned the system off after about 10 minutes which was before the moisture blockage problem could occur so I don't think I hurt anything but I'm not going to run the system anymore until the hermetic service kit arrives this wednesday and I can get some gauges on. This sounds like a good plan. I normally never charge liquid because that allows any residue from the can, gauge hoses, etc. to be "washed" into the system. It's much cleaner to charge vapor only. Do this by placing the can into a warm water bath (warmer than any point in the refrigerator system) to cause the liquid to evaporate from the can and re-condense in the system. Also, before recharging, you should "bake out" the system by placing a blanket over the entire fridge, and allowing a warm air heater to blow under the blanket. Direct the hottest air onto the compressor, with the rest getting warmed up by the air trapped under the blanket. Leave the vacuum pump and heater on overnight to dehydrate the system. The next day, put in a vapor charge of just enough refrigerant vapor to get the system out of a vacuum. Then replace the drier. Evacuate again after this, but it won't need heat nor longer than an hour. After that, charge as planned.
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jackj
New Member
Posts: 21
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Post by jackj on May 23, 2023 17:22:05 GMT
Hermetic service kit finally arrived today! I lucked out and was able to find a complete set that fits on this compressor. Now that I have a way to hook up to the system I tested the pressures and I need help explaining the numbers I found. With the system off and at an idle state after sitting for over a day I was at around 50psi and after starting the system after about 5 minutes I was only at 90 psi and it would not go any higher. Obviously I could not check the low side since there is no port. Would this low high side pressure further indicate a low charge condition? Or is the compressor not pumping correctly anymore? I'd rather not charge the system and add a drier if the compressor is shot. System still partially cooled the freezer section and even after the possible moisture blockage appeared the pressure was still at 90lbs. What do you all think? Attachments:
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Post by turbokinetic on May 23, 2023 17:24:33 GMT
Hermetic service kit finally arrived today! I lucked out and was able to find a complete set that fits on this compressor. Now that I have a way to hook up to the system I tested the pressures and I need help explaining the numbers I found. With the system off and at an idle state after sitting for over a day I was at around 50psi and after starting the system after about 5 minutes I was only at 90 psi and it would not go any higher. Obviously I could not check the low side since there is no port. Would this low high side pressure further indicate a low charge condition? Or is the compressor not pumping correctly anymore? I'd rather not charge the system and add a drier if the compressor is shot. System still partially cooled the freezer section and even after the possible moisture blockage appeared the pressure was still at 90lbs. What do you all think? Hi Jack. That pressure of 90 PSI is generated by the temperature of the condenser coil. In a moderate temperature room, that is about where R12 will be. It still sounds like a moisture blockage, to me.
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jackj
New Member
Posts: 21
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Post by jackj on May 23, 2023 17:44:32 GMT
Hermetic service kit finally arrived today! I lucked out and was able to find a complete set that fits on this compressor. Now that I have a way to hook up to the system I tested the pressures and I need help explaining the numbers I found. With the system off and at an idle state after sitting for over a day I was at around 50psi and after starting the system after about 5 minutes I was only at 90 psi and it would not go any higher. Obviously I could not check the low side since there is no port. Would this low high side pressure further indicate a low charge condition? Or is the compressor not pumping correctly anymore? I'd rather not charge the system and add a drier if the compressor is shot. System still partially cooled the freezer section and even after the possible moisture blockage appeared the pressure was still at 90lbs. What do you all think? Hi Jack. That pressure of 90 PSI is generated by the temperature of the condenser coil. In a moderate temperature room, that is about where R12 will be. It still sounds like a moisture blockage, to me. Hi David. Thanks for the quick reply! You are totally right I just looked at the pressures on the nameplate and saw 300lbs which is probably a maximum rating. Looking at the pressure charts confirm everything is good. I'll recover the refrigerant then pull a vacuum while simultaneously "baking the system" then we will go from there.
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Post by turbokinetic on May 23, 2023 20:23:05 GMT
Hi Jack. That pressure of 90 PSI is generated by the temperature of the condenser coil. In a moderate temperature room, that is about where R12 will be. It still sounds like a moisture blockage, to me. Hi David. Thanks for the quick reply! You are totally right I just looked at the pressures on the nameplate and saw 300lbs which is probably a maximum rating. Looking at the pressure charts confirm everything is good. I'll recover the refrigerant then pull a vacuum while simultaneously "baking the system" then we will go from there. Sounds good. Yeah those nameplates state the maximum test pressure for the low side and high side individually; as well as the maximum charge weight for any system using that compressor. It is not an exact charge amount for the system and must be charged by frost line (area of the evaporator actually freezing.) I would definitely recommend not trying to re-use this charge after recovery unless you are using a recovery-recycling machine which will ensure the purity is good. It should only take one can or so of refrigerant, so I would invest in new refrigerant so as to "play with a full deck of cards" so to speak. I do use recovery machines but typically on larger systems where I have just charged in a large volume of refrigerant of good quality, and have to remove it to make repairs. Old systems like this, particularly with a suspected moisture problem are probably best disposing of the old gas and starting over.
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jackj
New Member
Posts: 21
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Post by jackj on May 23, 2023 21:58:20 GMT
Sounds good. Yeah those nameplates state the maximum test pressure for the low side and high side individually; as well as the maximum charge weight for any system using that compressor. It is not an exact charge amount for the system and must be charged by frost line (area of the evaporator actually freezing.) I would definitely recommend not trying to re-use this charge after recovery unless you are using a recovery-recycling machine which will ensure the purity is good. It should only take one can or so of refrigerant, so I would invest in new refrigerant so as to "play with a full deck of cards" so to speak. I do use recovery machines but typically on larger systems where I have just charged in a large volume of refrigerant of good quality, and have to remove it to make repairs. Old systems like this, particularly with a suspected moisture problem are probably best disposing of the old gas and starting over. That's what I figured, wasn't thinking right. I have no plans of reusing the old refrigerant though, I just wanted to safely contain it rather than just venting it into the atmosphere since I know r12 is the ozone killing stuff and I got a can of 152a air duster ready to go already. I started pumping it down with the vacuum pump, but I am going to have to pipe the pump exhaust out the window since the residual refrigerant it's pulling out of the system is stinking the place up since the fridge is located in a basement. I'm going to make an exhaust pipe then I'll let the system sit under a vacuum and bake for a while.
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